Electrical system of heating



No. 748,749. PATENTED JAN. 5, 1904. E. H. K ITFIELD. ELECTRICAL SYSTEM 0]? HEATING.

APPLICATION FILED OUT. 26, 1903.

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PATENTED JAN. 5, 1904.

' E. H. KITFIELD.

ELECTRICAL SYSTEM OF HEATING.

APPLICATION FILED 0012a, 1903. N0 MODEL. s SHBETSSHEET z.

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PATENTED JAN. 5, 1904.

E. H. KITFIELD.

' ELECTRICAL SYSTEM OF HEATING.

APPLICATION FILED OCT. 26, 1903.

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m: nnnms PETERS w., morounlo. WASHINGYON, B4 c UNITED STATES Patented January 5, 190

PATENT OFFICE.

ELECTRICAL SYSTEM OF HEATlNG.

SPECIFICATION forming part of Letters Patent No. 748,749, dated January 5, 1904.

Application filed October 26. 1903.

To an whom it may concern.-

Be it known that I, EDWARD H. KITFIELD, a citizen of the United States, residing in Swampscott, in the county of Essex and State of Massachusetts, haveinvented an Improvement in Electrical Systems of Heating, of which the following description, in connection with the accompanying drawings, is a specification, like characters on the drawings representing like parts.

This invention relates to an electrical heating system applicable for general heating purposes, and particularly well adapted, among other uses, for heating buildings, houses, railway-cars (operating on electric railway systems,'and other structures and vehicles. i

The invention has for its object to provide an electrical heating system in which the supply of current to one or more electric heaters, which may be made in the form of coils and located in the car or other structure, is automatically governed by the tempera-' ture of the car or other structure, as will be described.

In the present instance I have shown the invention as applied to a system for heating an electric-railway car, and for this purpose I employ a circuit-controller which is operated by a thermostat located within the car to change the condition of the circuit when the temperature of the car reaches a predetermined point and means for maintaining the circuit through the heaters when the said circuit is opened by or at the thermostat.

Another feature of the invention consists in providing means. for selecting different temperatures at which the current may be applied to and cut off from the electric heaters, as will be described.

These and other features of this invention will be pointed out in the claims at the end of this specification.

Figure 1 represents an outline of an electricrailway car provided with a heating system embodying this invention; Fig. 2, a digrammatic View of the system represented in Fig. 1; Figs. 3 and 4, diagrammatic views like Fig. 2 to enable the operation of the system to be clearly comprehended, and Figs. 5 and 6 modifications to be referred to.

In the present instance I have chosen to illustrate my system in connection with an Serial No. 178,493. (No model.)

electric-railway car (indicated by the dotted lines in Fig. 1;) but it will be understood that I do not desire to limit the invention in this respect, as the system forming the subject of this invention is applicable to buildings, houses, and other structures.

In accordance with this invention the railway-oar a, which is provided with one or more electric heaters b of any suitable,'desired, or required construction, contains within it a thermostat which responds to the changes in temperature of the car and is employed to open and close the circuit containing the electric heaters, the said circuit being provided with means for maintaining the circuit through the electric heaters while the thermostat is moving from what may be termed its closed to its opened position, and vice versa.

In the present instance the thermostat, which may be of any suitable or desired construction, is represented as a coil provided with an arm a and made of two metal strips having different rates of expansion and contraction and commonly known as a thermostatic strip. The thermostat c cooperates with one or more circuit-terminals, (shown in Figs. 1 to 4 as five in number and marked (1 cf 9 71,) which are connected by conductors it Z m with the terminals or contact members 'n 0 p qrof a multiple circuit-controller provided with a movable contact member or arm 3, which is connected by a conductor 10 with a switch-arm 2 T, cooperating with a terminal 25, which is included in circuit with the source of current, herein represented as a trolley-wire 12, from which the current is conducted to the car by the trolley-pole 12-3 in the usual manner, the trolley-pole being connected by the wire 26 with the terminal 25.

The thermostat c is normally included in circuit with one or more of the electric heaters b. In the present instance the heaters b are arranged in series, having one end connected with the ground 15 and their other end connected by wire 16 to one end of the coil of an electromagnet or solenoid 17, the other end of which coil is joined by wire 18 with the thermostat c. The electromagnet or solenoid 17 is designed to maintain the circuit of the heating-coils b when the circuit is open at the thermostat c, and for this purpose the said solenoid governs the operation of a circuit-controller comprising, as herein shown, a movable member 20, which is attached to the core 21 of said solenoid and cooperates with a stationary member 22, preferably located within the solenoid 17, so as to be within the magnetic field of said solenoid, for a purpose as will be described. The contact member or terminal 22 is joined by wire 23 to the switch-arm 24.

The terminals 01 e f g h of the thermostatic switch or circuit-controller are joined by wires 30 31 32 33 34 to the terminals or contact members 35 36 37 38 39 of a multiple switch or circuit-controller provided with a movable contact arm or member 40,which is joined by the conductor 41 to the conductor 16, so that under conditions as will be described the coil of the solenoid may be shunted by the thermostat c. The core 21 of the solenoid 17 is connected with the conductor 18 by a wire 42, which forms part of the shunt-circuit for the solenoid, as will be described. The operation of the heating system as thus far described may be readily understood by reference to Figs. 1, 2, 3, and 4.

As represented in Figs. 1 and 2, the heating system is in what may be termed its normal condition, in which the current is cut off from the heating-coils and from the solenoid, the switch 24 being open, the switch-arm s being in contact with the terminal at, the switcharm 40 being in contact with the terminal 39, and the thermostat 0 being in contact with the terminal (Z, which position of the thermostat may be considered as its starting position.

To enable the invention to he clearly understood, let it be supposed that the terminals d efg h represent, respectively, 20, 30, 40, and of temperature. In this case the diagram Fig. 2 represents the temperature of the car as 20. By reference to Fig. 2 it will be observed that the circuit of the heaters and solenoid is open at the switch 24. To heat the car, the operator throws the switch 24 into engagement with the terminal 25 and completes the circuit through the heaters b, which circuit is indicated in Fig. 2 by the full-line arrows and may be traced as follows: from the trolley-wire 12 by the trolley-pole 13 and wire 26 to the switch 24,thence by wire 10, switch-arm .9, terminal 7t, and wire t' to the terminal d, with which the thermostat c is in engagement, thence by the thermostat 0, wire 18, solenoid 17, wire 16, and heaters Z) to the ground 15. The solenoid 1'7 is thus energized and moves its core 21, so as to bring the circuit-terminal 20 into engagement with the terminal 22 and complete a shunt-circuit for the thermostat 0, thereby maintaining the heaters 19 in circuit after the thermostat under theinfluence of heat leaves the terminal (1 and moves toward the terminal representing the maximum degree of heat to which it is desired the carshould be heated, which maximum degree may be 70 and is represented by the terminal h. The shuntcircuit is indicated bydotted arrows in Fig. 3 and may be traced as follows: from the trolley-wire 12 by pole 13 and wire 26 to switch 24, thence by wire 23, terminals 22 20, wire 42, wire 18, solenoid 17, wire 16, and heaters b to ground 15. By reference to Fig. 3 it will be observed that the circuit at the thermostat c is open and remains open until the said thermostat makes contact with the terminal 7t, representing 70, at which time the temperature of the car has reached 70. When the thermostat c engages the terminal 72., as indicated by dotted lines, Fig. 3, a shunt-circuit around the solenoid 17 is established, which may be traced as follows: from the trolleywire 12 by pole 13 and wire 26 to switch 24, wire 23, terminals 22 20, wires 42 18, thermostat c, terminal h, wires m 34, terminal 39, switch 40, wires 41 16, and heaters 19 to ground 15. As soon as the shunt-circuit around the solenoid is established as described the core 21 drops and separates the terminals 20 22, thereby opening the circuit through the heating coils and preventing the temperature exceeding 70, which may be regarded as the maximum. The current remains out off from the heaters 5 until a circuit through the said heaters is again established, which may be when the thermostat has contracted sufficiently to make contact with the terminal d; but I prefer to provide for reestablishing the circuit at different degrees between the maximum (represented as 70) and the minimum, (represented as 20.) To this end the intermediate terminals of the thermostatic circuitcontroller namely, 6, f, and g-are provided, which may represent temperatures of 30, 40, and 60,respectively.

In practice it may be desired not to have the temperature of the car while in service drop below 60, and in this case the operator places the switch sin engagement with the terminal q, as represented in Fig. 4, so that as the car cools off and the thermostat c contracts and moves off of the terminal h and onto the terminal g, as represented by dotted lines in Fig. 4, the circuit through the heaters is again established, which circuit may be traced as follows: from the trolley-wire 12 by pole 13 and wire 26 to switch 24, thence by wire 10 to switch .9, thence by terminal q, wire Z, terminal g, thermostat 0, wire 18, solenoid 17, wire 16, and heaters 11 to ground 15. The solenoid is again energized and attracts its core 21, thereby closing the shunt-circuit for the thermostat 0 between the terminals 20 22, which circuit may be traced as follows: from the trolley-wire by pole 13 and wire 26 to switch 24, thence by wire 23, terminals 22 20, wires 42 18, solenoid 17, wire 16, and heaters 19 to ground 15. The shunt-circuit around the thermostat and through the heaters 12 is m aintained until the temperature of the car again reaches 70, at which time the sl1unt-circuit around the solenoid is established, which circuit may be traced as follows: from the trolley-wire 12 by pole 13 and wire 26 to switch 24, thence by wire 23, terminals 22 20, wires 42 18, thermostat 0, terminal h, wires 1% 34, terminal 39, switch 40, wires 41 16,and heaters b to ground 15. As soon as the shunt around the solenoid is established as described the solenoid 17 is denergized and the core 21 drops, thereby opening the circuit of the heaters 5 between the terminals 20 22 until the car has cooled oif sufficiently to again close the circuit of the heaters at the terminal g by the contraction of the thermostat c.

It will thus be seen that in the case just described becomes the minimum and the maximum, between which points the temperature is maintained by the movement of the thermostat from the terminal g to the terminal h, and vice versa.

Any two terminals of the thermostatic switch may be coupled together as the maximum and minimum by means of the multiple switches 40 s, which switches may be designated the maximum and minimum selective switches, the switch 8 being moved onto the terminal selected as the minimum and the switch 40 being moved onto the terminal selected as the maximum. This arrangement enables the heating system to be operated with a minimum current and at a great saving, for in the case of electric cars they may be heated to a comparatively low temperature While standing in the car-barn, which may be for hours, and yet be heated sufficiently to enable them to be heated to the maximum heat in a substantially short timeas, for instance, when they are put into service. To illustrate, while the car is not in use the switch .9 may be placed on the terminal 0, representing 30, and the switch 40 on the terminal 37, representing 40, in which case the heaters b are automatically cut out of circuit when the temperature reaches 40 and are cut in circuit when the temperature falls to 30.

While I may prefer to employ a thermostatic circuit-controller provided with a series of terminals corresponding to different temperatures and selective switches cooperating therewith, as above described, I do not desire to limit my invention in this respect, as the selective switches may be dispensed with and a thermostatic switch having a maximum terminal and a single minimum terminal may be employed, as represented in Figs. 5 and 6, wherein the thermostatic switch 0 is shown as normally in contact with the minimum terminal 50, connected by wire 10 with the switch 24, and as adapted to be expanded into contact with the maximum terminal 51, to which is connected the wire 41. The operation of the system shown in Figs. 5and 6 is the same as that shown in Figs. 1 to 4, the solenoid 17 acting to shunt the thermostat c as soon as the current is turned on at the switch 24'and the thermostat acting to shunt out the solenoid when the maximum temperature is reached.

The circuit-terminals 2O 22 are and may be located in the magnetic field of the solenoid 17, so that any are which might be formed between said terminals may be ruptured or blown out by said field.

I claim- 1. In an electrical system of heating,in combination, a heater, a circuit in which said heater is included, a thermostatic circuit-controller, a solenoid in circuit with said heater, and a circuit-controller operated by said solenoid, substantially as described.

2. In an electrical system of heating,in combination, a heater, a circuit in which said heater is included, a thermostat controlling said circuit, and an electromagnet in said circuit and controlling a shunt-circuit around said thermostat, substantially as described.

3. In an electrical system of heating,in combination, a heater, a circuit in which said heater is included, a thermostat controlling said circuit, and an electromagnet in said circuit and controlling a shunt-circuit around said thermostat, and a shunt-circuit for said electromagnet controlled by said thermostat, substantially as described.

4. In an electrical system of heating,in combination, a heater, a circuit in which said heater is included, a thermostat controlling said circuit, an electromagnet in said circuit and controlling a shunt-circuit around said thermostat, and temperature-selective switches governing the circuit of said heater, substantially as described.

5. vIn an electrical system of heating,in combination, a heater, a circuit in which said heater is included, a thermostat controlling said circuit, and means for maintaining the circuit of said heaters when said circuit is open at the said thermostat, substantially as described.

6. In an electrical system of heating,in combination, a heater, a circuit in which said heater is included, and a thermostat controlling said circuit to cut out said heater when the temperature reaches a predetermined point and to include said heater in circuit when the temperature falls to a predetermined point, substantially as described,

7. In an electrical system of heating,in combination, a heater, a circuit in which said heater is included, and a thermostat controlling said circuit to cut out said heater when the temperature reaches a predetermined point and to include said heater in circuit when the temperature falls to a predetermined point, and a translating device to maintain the circuit of theheater when the said circuit is opened by the thermostat, substantially as described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

EDWARD H. KITFIELD.

WVitnesses:

JAs. H. CHURCHILL, J. MURPHY. 

